Werberology: Question regarding float levels/ needle valve

Played around with my recently rebuilt carbs a bit yesterday. It seems as though things are running a good bit on the rich side. So I opened up the tops and checked that the float level was correct one more time prior to synching everything up. I found that, despite all the floats measuring at 48mm on the vertical measurement, that two of the floats were bottoming out on the top of the float housing on the carb itself, hard to tell if the needle valve was able to fully close and seat or not. Corrected the problem the best I could but on one carb it seems as though I had to push things out by about 2mm to avoid bottoming out on the carb housing when fully shut.

Last night I read through the service manual for clues. I have a copy of both 78-79 GTB/GTS and the earlier GT4 manuals. In the GT4 manual it states "make sure that the new valve is perfectly tight in the proper guide". Not sure if this is referring to the needle valve and it it's accompanying housing that screws into the carb being properly tightened into the carb itself, or if it is referring to the needle valve sitting tightly into the accompanying housing. Did not give it much thought before, but none of my needle valves fit securely into the housing that screws into the carb top. If you hold my carb tops perpendicular with the ground the needle valves will come all the way out of the housing to the point that the only thing holding the needle valve into the housing is the tongue on the float itself. Is this correct or do I have something wrong with my needle valves? Looking at the needle valves that I have it does not seem that there is any way that they can fit securely into the accompanying housing, it is perfectly round.

Don't have any pictures at the moment, but could snap some of it would help clear things up.